OBJECTIVE:
To estimate the contribution of work-related diseases to sick leaves due to
general and occupational health problems.METHODS: Sociodemographic, occupational and health data from 29,658 records
of temporary disability benefits, granted on account of health problems by the
Instituto Nacional do Seguro Social (National Institute of Social Security)
in the state of Bahia (Northeastern Brazil), were analyzed. All constant ICD-10
clinical diagnoses were taken into consideration, except for those referring
to external causes and factors that influence contact with health services.
The link between diagnosis and occupation was based on the ICD-10 code and whether
the type of compensation was due to a "work-related accident/disease" or not.RESULTS: From all the benefits, 3.1% were granted due to work-related
diseases: 70% were musculoskeletal system and connective tissue diseases, while
14.5% were related to the nervous system. In general, benefits granted at more
than two times the expected frequency were as follows: tenosynovitis in the
manufacturing sector (Proportion Ratio-PR=2.70), carpal tunnel syndrome in the
financial intermediation sector (PR=2.43), and lumbar disc degeneration in the
transportation, postal service and telecommunications sectors (PR=2.17). However,
no causal connection could be established for these diseases, in these activity
sectors, in a significant percentage of benefits.CONCLUSIONS: Results suggest the existence of possible occupational risk
factors for diseases in these fields of activity, as well as the underreporting
of the link between diseases and work, thus disguising the responsibility of
companies and the perspective of prevention through work reorganization.

Despite the fact
that work-related diseases (WRD) are recognizably avoidable, they are responsible
for most of workers' morbidity and, may cause disability and even death.8
In Brazil, WRD claims have increased from 5,025 in 1988 to 30,334 in 2005, among
workers under the Regime Geral da Previdência Social (Social Security
General System),a resulting in an increment
of occupational benefits for lost wage compensation. On the other hand, there
has been a decreasing tendency for the occurrence of these diseases in developed
countries. In the United States, the 2002 Bureau of Labor Statisticsb
registered 294,500 WRD claims, a number that dropped to 242,500 in 2005.b
In Ontario, Canada, the estimated WRD rates, based on benefit payments, decreased
by approximately 50% in the last decade.10

The causes suggested
for the decrease in WRDs are many, from underreporting9 to macro-economic
factors, such as demographic changes in the workers' population and in the employment
distribution among economic trades.10 Another determinant factor
could be the primary prevention in the workplace. Controversies over explanations
for these changes in the occupational morbidity profile have been observed worldwide
and sparked debates about the required changes in the approach towards workers'
healthcare and prevention.

Overall, information
on the WRD magnitude and the establishment of diagnoses come from governmental
institutions. In developed countries, despite restrictions, the most frequently
used sources to learn about WRDs are the Workers' Compensation Insurance data,
a specific type of insurance to compensate workers' lost wages when affected
by work-related diseases/accidents. Driscoll et al5 mention that
one of the advantages of these databases is the existence of standard systems
to confirm cases and register information. On the other hand, they have important
limitations: they only include employees; they may exclude trades such as the
armed forces and agriculture workers, who are usually self-employed; and also
WRD underreporting, due to the difficulty to establish an occupational causal
connection.

In Brazil, workers
under the Regime Geral da Previdência Social who may be granted
WRD benefits are employed workers, self-employed professionals, and special
insurance holders. The specialized medical doctors from the Instituto Nacional
do Seguro Social - INSS (National Institute of Social Security), a governmental
institution linked to the Ministry of Social Security, are the ones responsible
for establishing a causal connection between diseases and work. Among employed
workers, this only happens in case of harmful situations involving sick leaves
longer than 15 days, when the INSS pays for those unable to work. The establishment
of a causal connection is based on the expert's clinical and epidemiological
knowledge, according to a WRD list prepared by the Ministry of Social Security.
Until March of 2007, the INSS required that a Comunicação
de Acidente de Trabalho (CAT - Work-related accident communication) was
issued to characterize a work-related disease. However, beginning in April of
2007, the causal connection is also established based on the Nexo Técnico
Epidemiológico (Epidemiological-Technical Connection), which means,
an excess of risk related to the workers' industrial trade, regardless of the
CATc being issued.

To be aware of
the contribution of WRDs to the sum of leaves due to general and occupational
health problems, as well as their distribution among the several economic trades
and respective, most frequent diagnoses, may subsidize decisions aimed towards
the adoption of preventive measures. Moreover, this will help to promote public
debate over the impact of these health problems on social insurance.

The objective of
the present study was to estimate the proportion of temporary disability compensation
claims on account of work-related diseases.

METHODS

This is a cross-sectional
study that used records of benefits granted by the INSS due to general and work-related
health problems which led to temporary disability, in the state of Bahia, in
2000. These records were obtained from the INSS' Sistema Único de
Benefícios (SUB - Unified System of Benefits). A total of 29,663
benefits were granted on account of temporary occupational disability in this
state. Of these, five were excluded from the analysis as they did not include
the clinical diagnosis. The total number of benefits studied was 29,658.

The benefits granted
due to work-related accidents and diseases are coded as B91 by the INSS; whereas
those due to health problems that are not related to work are coded as B31.
The total study population involved all insured workers in the period who were
eligible to receive these two types of benefits. They were, thus, under the
Regime Geral da Previdência Social, from which domestic workers,
individual contributors (self-employed professionals), civil servants and non-contributing
workers are excluded. The study observation units were all paid B91 and B31
benefit records, except for the clinical diagnoses corresponding to chapter
XV of the ICD-10 (pregnancy, childbirth and puerperium).

The SUB is the
INSS' data registry system, processed by the DATAPREV, the Ministry of Social
Security's technology and information company, where each social security event
is registered, thus originating the concession of a benefit. These registers
include the company's and the employee's data: company's trade, according to
the Classificação Nacional de Atividade Econômica
(CNAE - National Economic Activity Classification); health problem diagnosis,
according to the 10th revision of the International Classification
of Diseases (ICD-10); and data on the beginning, duration and type of benefit.

The disease variable
was created (1=yes, 0=other diagnoses), defined as all the ICD-10 clinical diagnoses,
except for those that characterize accidents, included in chapters XIX (injuries,
poisoning, and certain other consequences of external causes) and XXI (factors
influencing health status and contact with health services), which were considered
as other diagnoses. Diseases were classified in accordance with ICD-10 groups.
Three specific diagnoses were taken into consideration in the analysis, the
carpal tunnel syndrome (G56 and G56.0), tenosynovitis (M65, M65.8, M65.9) and
intervertebral disc degeneration (M51). Other variables analyzed were as follows:
type of benefit, whether it was related to work (B91) or not (B31), and company's
trade (according to the CNAE).

Proportion comparisons
were performed, but statistical inference was not, as all benefits were taken
into consideration, rather than a sample. To calculate the proportion ratios
(PR), the sum of benefits was considered as reference. Prevalence was not estimated
because denominators were the sum of benefits, instead of the population from
which cases come from. The databases were provided by the Ministry of Social
Security and the analysis was performed using the SAS 8.1 statistical software.
There were no individual identification data about beneficiaries or companies.
As the data were administrative in nature, the study protocol was not submitted
to a Research Ethics Committee.

RESULTS

Of all the benefits,
17,282 (58.3%) were granted due to diseases; 6,499 (21.9%) due to injuries,
poisoning and other external causes; and 5,877 (19.8%) due to factors that influenced
health status and contact with health services, according to the ICD-10th
Review.

Work-related diseases
represented 3.1% (935) of all the temporary disability benefits granted on account
of health problems in general. In terms of trade, this percentage varied from
1.2%, referring to undeclared CNAE, to 7.4% in the manufacturing trade, where
the proportion of benefits per WRD was more than double the expected rate (PR=2.31).
Similarly, the trade entitled "financial intermediation, real estate, leases,
services and public administration" showed 7.2% of WRDs (PR=2.25). Workers in
the retail, storage and food trades showed the lowest percentages of WRDs (2.7%),
among the benefits related to health problems in general. A low percentage of
WRDs (2.7%) was also observed among benefits with undeclared CNAE (54%, 16,014)
(Table 1).

Of all the temporary
disability benefits granted due to work-related accidents and diseases, the
WRDs contributed with 27.6%. Only in the "financial intermediation, real estate,
leases, services and public administration" trade did the WRDs comprise the
majority of benefits (53.5%), a percentage almost two times greater than the
total (PR=1.93). The group entitled "retail, storage and food trades" had the
lowest WRD proportion (17.8%). The percentage of undeclared CNAE for benefits
on account of work-related health problems was significant (26.8%) (Table
1).

Only 935 (5.4%)
temporary disability benefits granted due to diseases were related to work.
The ICD-10 groups that ranked high in the sum of benefits were the following:
musculoskeletal system and connective tissue diseases (37.2%), diseases of the
circulatory system (19.3%) and behavioral and mental disorders (10.9%). By analyzing
WRD benefits exclusively, it could be observed that musculoskeletal system and
connective tissue diseases (70%) ranked high, followed by diseases of the nervous
system (14.5%) (Table 2).

Table
3 shows the proportion of both types of benefits, granted to people suffering
from carpal tunnel syndrome, tenosynovitis, and lumbar intervertebral disc degeneration,
out of the sum of benefits granted due to temporary disability, according to
the industrial trades. The proportion of benefits for tenosynovitis varied from
1.2% in the "construction, electricity, and gas" activity group to 6.2% among
workers from the manufacturing trade. By taking the proportion of benefits for
tenosynovitis from the total number of benefits granted on account of diseases
(2.3%) as reference, almost three times more benefits for tenosynovitis were
given to the manufacturing trade (PR=2.70) than what was expected. Important
estimates were also calculated among workers from the financial intermediation,
real estate, leases, services, and public administration trades (PR=2.09); transportation,
postal service, and telecommunications trade (PR=1.61); and health and social
service trade (PR=1.61). Groups from the "construction, electricity and gas"
and "retail, storage, and food" trades showed the smallest proportions of benefits
for tenosynovitis, 1.2% and 2.2%, respectively.

Benefits for carpal
tunnel syndrome represented 1.4% of those granted for diseases in general. The
proportions of benefits for this syndrome, regardless of the relationship with
work, were greater than those from the comparison group in the following trades:
"financial intermediation, real estate, leases, services, and public administration"
(PR=2.43), "health and social services" (PR=2.43), "education, and recreational,
cultural and sport activities" (PR=1.86), "manufacturing trade" (PR=1.78), "retail,
storage, and food" (PR=1.28), and "transportation, postal service, and telecommunications"
(PR=1.14). Only workers from the "construction, electricity and gas trades"
and the "undeclared CNAE" group had smaller proportions for carpal tunnel syndrome
than what was expected, 0.5 and 0.7, respectively (Table
3).

Of the three health
problems assessed, benefits due to lumbar intervertebral disc degeneration had
the greatest contribution: 3% of the sum of temporary disability benefits granted
on account of diseases. In the "transportation, postal service, and telecommunications"
trade, the proportion of benefits on account of this disorder was greater (6.5%).
Other trades showed proportions that were a little above the comparison group,
except for "financial intermediation, real estate, leases, services, and public
administration", which had estimates of 2.4%, and "undeclared CNAE", with 2.7%
(Table 3).

Table
4 shows the proportions of temporary disability benefits granted on account
of carpal tunnel syndrome, tenosynovitis, and lumbar intervertebral disc degeneration,
per type of benefit and trade. Only in four situations were greater proportions
of work-related benefits observed, compared to those that were not related:
carpal tunnel syndrome in the "financial intermediation, real estate, leases,
services and public administration" group of activities (69.5%), and tenosynovitis
among workers from the "manufacturing trade" (60%), "transportation, postal
service, and telecommunications" (53.8%) and "financial intermediation, real
estate, leases, services, and public administration" trade groups (65.8%). Even
in these situations, at least one third of benefits were granted as not work-related.

DISCUSSION

The findings from
the present study must be viewed with caution because of database limitations.
One piece of evidence of such limitations is the great number of benefits without
a record of the company's economic trade, which varied from 54% for temporary
disability benefits related to health problems in general to 26.8% for those
related to work. In addition, these benefits correspond to leaves from work
longer than 15 days, which presume greater severity of the diseases studied.
Thus, diseases that do not potentially lead to leaves from work and those involving
shorter leave periods are not entitled to benefits.

Another limitation
to the study was that information on possible risk factors for health was not
available. Such information, which includes age, sex, time of employment and
occupational background, could interfere with the CNAE registered when the benefit
was granted.

Work-related diseases
with an occupational causal connection recognized, according to the INSS characterization,
did not stand out in the group of general health problems that resulted in leaves
from work, representing 3.1% of all the health problems. However, this percentage
varied according to the trade assessed. The difference between the WRD percentage
of the "manufacturing trade" and "financial intermediation and others" (7%)
and that of "retail" and "health and social services" (4%) is probably due to
distinct occupational exposures in the workplace and the workers' level of knowledge
of occupational diseases, their rights and benefits. Workers' awareness of health
and safety rights is one of the factors known to determine more records of occupational
health problems.13 In the state of Bahia, the bank and (chemical,
oil, metal) manufacturing trade unions are recognizably more active in the area
of occupational health than others.

Work-related diseases
represent less than 30% of all the temporary disability benefits granted on
account of health problems related to work, as expected, once it is less difficult
to establish a causal connection for typical accidents in relation to diseases.
The only exception occurred in the "financial intermediation and others" trade,
where the WRDs were the majority. In this field, risk factors for occupational
diseases, such as ergonomic ones, are more prevalent in the workplace, compared
to those that cause typical accidents.

The main causes
of benefits granted due to diseases in general, regardless of their relationship
with work, were musculoskeletal system and connective tissue diseases, diseases
of the circulatory system, and behavioral and mental disorders. In a study performed
with social security benefits in the city of Porto Alegre (Southern Brazil)
restricted to the B31 code, the most common diseases were the same found in
this study, except for the rank order, with diseases of the circulatory system
in place of the behavioral and mental disorders.2

The WRDs that predominated
(84.5%) were musculoskeletal system and connective tissue diseases and those
in the nervous system, corresponding, in their majority, to cumulative trauma
disorders or osteomuscular work-related diseases (CTD/OWRD): muscle, nerve,
tendon, joint, cartilage and intervertebral disc dysfunctions. The proportion
of CTD/OWRD found in this study is substantially greater than those from other
locations where musculoskeletal disorders are also prevailing. In outpatient
services for occupational health in the state of São Paulo, musculoskeletal
system diseases represented the main cause of service (56%), followed by diseases
of the nervous system and sense organs (20.8%).15 However, the percentage
of CTD/OWRD was greater than the 56% reported, if carpal tunnel syndrome is
included, as this is a peripheral nervous system disease that could also be
considered as CTD/OWRD. In Canada, data from the Workers' Compensation System
reveal that musculoskeletal diseases correspond to 54.4% of the WRDs leading
to leaves from work.6 In the United States, these diseases are also
predominant, whether among those that generated insurance compensation benefits
for work-related health problems (52.2%), or among the others that are registered
in the Department of Labor by private companies (53.4%).7 This difference
in proportion of musculoskeletal diseases may be due, among other factors, to
distinct classification criteria of disease groups. Moreover, underreporting
of other types of WRDs must be considered in the state of Bahia, which would
artificially raise the proportion of CTD/OWRD.

Ear diseases did
not appear with a significant percentage among the causes that led to occupational
disease benefits. However, they represented one of the main WRDs in a survey
conducted by the INSS, using CAT data and not taking into consideration leaves
from work.d Noise-induced
hearing loss is the most common and severe work-related disease, whose treatment
is limited. Workers who are thus diagnosed are usually sent to the INSS for
medical evaluation. Thus, the CAT is issued without a leave and, as a result,
does not generate a benefit, which explains the low reporting of this health
problem observed in the present study.

Other health problems
that are usually related to work and require leaves from work, such as certain
respiratory system and skin diseases, appeared in smaller percentages, thus
suggesting underreporting. It must be emphasized that there was one single record
of benefit granted on account of work-related cancer. From a more conservative
point of view, once occupational exposure is considered to be responsible for
about 4% of all cancer cases,4 a total of 30 benefits due to this
health problem would be expected, instead of just one.

The findings from
the present study suggest occupational risk factors for the three diseases analyzed
separately. The assessment of tenosynovitis, carpal tunnel syndrome and lumbar
intervertebral disc degeneration per field of economic activity revealed a relative
excess among workers from certain activities in relation to the reference group.
By employing a conservative estimate that diseases recorded in certain trades,
with double the frequency observed in the sum of benefits, may be related to
work, substantial underreporting of the relationship with work can be verified.
Carpal tunnel syndrome and tenosynovitis are in the List of Work-Related Diseases,
included in the Annex II of the Regulamento da Previdência Social
(Social Security Regulation).e
Even though it is not included in this list, lumbar intervertebral disc degeneration
is present in an indirect way, once its symptomatology (dorsalgia, sciatica,
lumbago with sciatica) is present. Thus, the health problems above mentioned
were not characterized as work-related on account of legal impediment.

It is implausible
to assume that these findings are restricted to the location of study, namely
the state of Bahia, even if they are limited to these health problems exclusively.
On the contrary, information from the Ministry of Social Security shows that
in 2005, Bahia was the state with highest incidence of work-related diseases,
2.0 per 1,000 records,f whereas
in the country it was 1.2 per 1,000 records.g
However, as this may better reflect the register capacity and the level of implementation
of occupational health practices in the country, whereas the risk of health
problems would not be as well reflected, it is possible that the underreporting
situation in other states could be even greater. Despite the increase in occurrence
of WRDs in Brazil, underreporting of occupational health problems remains high,
similarly to what has been observed in terms of typical work-related accidents
due to external causes.12 The reasons for this underreporting have
already been discussed by several authors,3,11,14 and range from
the changes in the social security legislation, thus extending the period without
insurance payment to 15 days, to the employer's failure to issue the CAT to
avoid responsibilities, such as the employee's guarantee of stability, withdrawal
from the Fundo de Garantia por Tempo de Serviço - FGTS (social
security fund based on time of service), in addition to maintaining the company's
reputation.

As regards WRDs,
another factor that may increase underreporting is the controversy over causality.
Unlike typical occupational accidents, whose connection with work is less subjective,
it is more difficult to establish a causal connection with work when it comes
to occupational diseases. Among diseases whose origin is exclusively due to
work, such as asbestosis, silicosis, and mesotelioma, the difficulty to recognize
the causal connection is primarily related to the very long latency period between
exposure and the first disease symptoms, rather than the uncertainties about
occupational causality. Currently, however, the predominant diseases in the
workplace are those whose causal agent is not only work, frequently occurring
in the non-working population as well or having non-occupational causes, such
as CTD/OWRD, hearing losses, upper respiratory tract diseases, asthma, and mental
disorders, among others. Thus, the causal connection for these health problems
has caused conflicts to arise among companies, insurance companies, and workers
all over the world. Biddle et al1 compared compensation insurance
data on work-related health problems in Michigan, United States, to occupational
diseases notified by health professionals, and found that 55% of workers with
these diseases did not seek insurance. Morse et al9 observed that
only 7% of work-related musculoskeletal diseases were registered in the compensation
insurance records as work-related health problems in Connecticut, United States,
between 1995 and 2001.

Underreporting
harms workers who, by not having the disease characterized as work-related,
do not have their rights recognized. On the other hand, it hinders the making
of public policies to prevent occupational diseases and accidents, once there
is no reliable information about these health problems available. Thus, the
Ministry of Social Security's initiative to adopt the Nexo Técnico
Epidemiológico to establish a causal connection between the health
problem and work is positive. This methodology considers a health problem having
higher incidence among workers of a certain trade in relation to the average
morbidity of the remaining working population as the identification criterion
for WRDs. The first effects of the Nexo Técnico Epidemiológico
can already be seen when compensations due to work-related diseases or accidents
are granted. In April of 2007, when the Nexo Técnico Epidemiológico
became effective, a total of 28,594 benefits were granted all over Brazil, a
number 147.8% greater than the previous month's.h
Thus, it is expected that the making of public and private policies to prevent
occupational health problems will be enhanced, based on more consistent information.
Thus, studies performed after the implementation of the Nexo Técnico
Epidemiológico could reveal the gap between what has been considered
to be WRD and the actual occupational morbidity among workers covered by the
Regime Geral da Previdência Social.